Turbulent Cascade Features and Scale Imprint Characteristics in a Wind Plant Near-Wake

Scale evolution statistics are used to analyze the flow structure of the wake flow in the boundary layer of a wind turbine array. A 3 x 3 wind turbine array is tested experimentally via x-type hot-wire anemometry, and provided a 9 x 21 of velocity signal downstream the rotor.  It is observed that the structure evolution tends towards the non universality as the distance from the rotor is reduced. Flow structures of the wakes are characterized via correlation between the velocity and multifractal Holder exponent related to the velocity increment via Frisch-Parisi conjecture. Flow events are also classified using the sign of the fluctuating streamwise velocity and the Holder exponent into four quadrants. A second and fourth quadrants of the velocity and the intermittency is dominant at the hub height and bottom tip. Hole-size filtering shows the variations in the number of record per quadrant and finding the fourth quadrant dominant. Further, the statistical properties of velocity-intermittency quadrant are interpreted in regards to the dependence between the velocity and velocity increments.